This may be more hassle than it's worth and it may not even work, but you can try.
You could capture now in FCP the pn footage. I believe that the 24pn footage is converted to 24p through the firewire.
Rendering might be faster though.
If you bring in 24p footage from P2 (or Firestore) and remove duplicate frames, then you have 23.98 footage that you can put on the same timeline as 24pNative material.